Degree'ing cam....ICL problems
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Degree'ing cam....ICL problems
LS1 with a cloyes hex adjust timing set with 3 keyway crank gear. degreeing the cam I got the intake duration dead on at 224. I moved on with the comp instructions to find ICL and it is off. My cam is 114 LSA 114 ICL so 0* advance or retard ground in. I installed the crank gear on the advance position, and the hex adjust is at zero which Cloyes says advances the Crank 4* meaning it should only advance cam timing 2* (called them to verify this). I was hoping to see 112 ICL but I am getting 109........ tried it 3 times. Is it possible the crank keyway was cut wrong or is it possible I could have jacked something up?
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It is in the hex adjust. the are some what sloppy. you need to play with it until your degree wheel reads correctly. Then check you cams opening and closing events to make sure it is correct. Its going to be a pain in the ***.
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Well thats good to know that these arent as accurate as advertised. Im surprised that the hex adjust could throw off ICL by 3 degrees. But I wound up just adjusting the hex until I got the 112 ICL that I wanted. Now to put the thrust bearing on I forgot earlier and re-do it haha. I feel better now, I thought that I screwed something up.
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Degree by .050 specs.... You have known values on your cam card..
Shape of the lobe could put it in a slightly different center point.
Many lobes are asymmetrical, and many lobes are different in how long it sits at the top of the lobe, so your top of lobe values are usually not a good option for degreeing a cam.
Shape of the lobe could put it in a slightly different center point.
Many lobes are asymmetrical, and many lobes are different in how long it sits at the top of the lobe, so your top of lobe values are usually not a good option for degreeing a cam.
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Yeah I did the intake duration at .050 which was dead on at 224, then moved on to ICL next, before I was going to put the dial indicator on the exhaust valve. Thats where I ran into the problems I had. I planned on dialing in ICL then re-checking intake duration at .050 again, then moving the dial to the exhaust side to check exhaust duration at .050 sound like a good idea?
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Degree by .050 specs.... You have known values on your cam card..
Shape of the lobe could put it in a slightly different center point.
Many lobes are asymmetrical, and many lobes are different in how long it sits at the top of the lobe, so your top of lobe values are usually not a good option for degreeing a cam.
Shape of the lobe could put it in a slightly different center point.
Many lobes are asymmetrical, and many lobes are different in how long it sits at the top of the lobe, so your top of lobe values are usually not a good option for degreeing a cam.
I see what your saying. But if I check duration at .050 on both intake and exhaust and they match the cam card, then I check ICL and it is off, I should just change the ICL with the hex adjust until it is where I want it correct? Or are you saying that because my lobes may not be asymetrical, I might already be at 112 ICL even though my degree wheel is telling me 109?
thanks for input.
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I see what your saying. But if I check duration at .050 on both intake and exhaust and they match the cam card, then I check ICL and it is off, I should just change the ICL with the hex adjust until it is where I want it correct? Or are you saying that because my lobes may not be asymetrical, I might already be at 112 ICL even though my degree wheel is telling me 109?
thanks for input.
thanks for input.
#12
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Degree by .050 specs.... You have known values on your cam card..
Shape of the lobe could put it in a slightly different center point.
Many lobes are asymmetrical, and many lobes are different in how long it sits at the top of the lobe, so your top of lobe values are usually not a good option for degreeing a cam.
Shape of the lobe could put it in a slightly different center point.
Many lobes are asymmetrical, and many lobes are different in how long it sits at the top of the lobe, so your top of lobe values are usually not a good option for degreeing a cam.
As far as the hex adjust being a pos, it's just not the case. You aren't looking for jewell like precision there. Just a method to move the cam. The +/- marks are there just for reference, not to be used for anything exact.
If you have ever set the cam timing using the offset bushings, they aren't any more accurate and way more of a pain in the *** to set up. They have slop as well.
Ron
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Thanks for the help, I got it done just took some twerking with the hex adjust. My numbers were a little off from the cam card....Ive heard 1 or 2 degrees is normal but heres what I got, sound normal? specs are at .050
Cam Card.................My results
224 / 230................225/233
.581/ .591................580/.586
Cam Card.................My results
224 / 230................225/233
.581/ .591................580/.586
#14
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Thanks for the help, I got it done just took some twerking with the hex adjust. My numbers were a little off from the cam card....Ive heard 1 or 2 degrees is normal but heres what I got, sound normal? specs are at .050
Cam Card.................My results
224 / 230................225/233
.581/ .591................580/.586
Cam Card.................My results
224 / 230................225/233
.581/ .591................580/.586
for my recent cam install, I checked 7 points at all 16 lobes. the average duration at .050 within 0.5-deg of spec for intake and exhaust. The installed centerlines were within 2-deg, and the LSA was within 0.5-deg. Of course there is a measurment tolerance on our side, I'd say that is about 1-deg or so.
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I wouldn't judge the accuracy of the grind by only measuring 2 lobes. Even though my average value for the durations was within .5-deg, individual min and max were nearly a 2-deg spread.
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Oh ok, yeah I guess I should measure at other lobes to see what I get. Update: I started from scratch, found absolute TDC insured the wheel is centered perfectly this time, it wasnt last time.
I have only checked the intake side so far, and looks good but have an issue still. I used the ICL method of finding .050 before and after max lift and averaging the numbers got 110.6 ICL. Then I did the same thing but at .100 before and after and got 110.8 ICL.
I then found in my LS1 engine building book a "more accurate method of finding ICL" which is finding degree wheel pointer position at .050 after intake lift starts, and .050 just before intake valve closes then averaging those numbers. With this method I got 112.3 ICL
Im not sure what to do at this point as I was hoping to see 112 ICL on all measurements. Atleast Im enjoying learning this stuff!
I have only checked the intake side so far, and looks good but have an issue still. I used the ICL method of finding .050 before and after max lift and averaging the numbers got 110.6 ICL. Then I did the same thing but at .100 before and after and got 110.8 ICL.
I then found in my LS1 engine building book a "more accurate method of finding ICL" which is finding degree wheel pointer position at .050 after intake lift starts, and .050 just before intake valve closes then averaging those numbers. With this method I got 112.3 ICL
Im not sure what to do at this point as I was hoping to see 112 ICL on all measurements. Atleast Im enjoying learning this stuff!
#20
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Degree by .050 specs.... You have known values on your cam card..
Shape of the lobe could put it in a slightly different center point.
Many lobes are asymmetrical, and many lobes are different in how long it sits at the top of the lobe, so your top of lobe values are usually not a good option for degreeing a cam.
Shape of the lobe could put it in a slightly different center point.
Many lobes are asymmetrical, and many lobes are different in how long it sits at the top of the lobe, so your top of lobe values are usually not a good option for degreeing a cam.
1-2 degrees won't make that much of a difference as others have said.